Find out the latest thinking about our universe.
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Even though the Universe is constantly changing, most processes are too slow to be observed within a human lifespan. However, the Stingray Nebula is now offering scientists a special opportunity to observe a system’s evolution in real time.
Images captured by Hubble in 2016, when compared to Hubble images taken in 1996, show a nebula that has drastically dimmed in brightness and changed shape. Bright blue shells of gas near the centre of the nebula have all but disappeared, and the wavy edges that earned this nebula its aquatic-themed name are virtually gone. The young nebula no longer pops against the black velvet background of the distant Universe.
Researchers discovered unprecedented changes in the light emitted by glowing gas — nitrogen, hydrogen and oxygen — that is being blasted off by the dying star at the centre of the nebula. The oxygen emission, in particular, dropped in brightness by a factor of nearly 1000.
The researchers note that while speculating on causes for this surprising finding, it’s important to explore the properties of the dying star at the centre of the Stingray nebula, which influences the structure and brightness of the nebula.
Observations from 1971 to 2002 showed the temperature of the star skyrocketing to almost ten times hotter than the surface of our Sun. Reindl speculates the temperature jump was caused by a brief flash of helium fusion that occurred outside the core of the central star. After that the star began to cool again, returning to its previous stage of stellar evolution.
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Astrophysicists attribute this to the fact that in its center it has an unusual star - SAO 244567. Earlier studies have shown that at first the temperature of this star rose sharply from less than 40 thousand to 108 thousand degrees Fahrenheit, and then began to fall and emit less ionizing radiation. Thus, the white dwarf itself undergoes very rapid changes. Scientists cautiously speculate that if the decay processes continue, the Stingray Nebula will completely disappear from the sky over the next 20-30 years.